K
Q

How to overrwite directory using kubectl cp

2/14/2020

I am copying a local directory into Kubernetes pod using kubectl cp command

kubectl cp test $POD:/tmp

It copies the test directory into Kubernetes pod /tmp directory.

Now I want to overwrite the test directory in the pod. I did not find any option to overwrite directory while copying using kubectl cp command.

Currently, I am deleting the test directory from the pod and then copy the directory.

kubectl exec $POD -- sh -c 'rm -rf /tmp/test'
kubectl cp test $POD:/tmp

This is working fine, but in case any error comes while copying, existing directory from pod will also be deleted.

How can I overwrite the pod directory with a local directory without deleting the pod directory first?

Thanks in advance.

-- Kishore
cp
kubectl
kubernetes
overwrite

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2 Answers

2/14/2020

Currently there is unfortunatelly no way to achieve your desired state with kubectl cp command.

If there are some undocumented features, please feel free to edit this answer and provide the solution, but currently there is no single place in documentation that could suggest the opposite.

Neither here nor in the context help of the kubectl command, available by running kubectl cp --help, there is no option mentioned that would modify the default operation of thekubectl cp command, which is basically a merge of the content of the already existing directory and copied one.

$ kubectl cp --help
Copy files and directories to and from containers.

Examples:
  # !!!Important Note!!!
  # Requires that the 'tar' binary is present in your container
  # image.  If 'tar' is not present, 'kubectl cp' will fail.

  # Copy /tmp/foo_dir local directory to /tmp/bar_dir in a remote pod in the default namespace
  kubectl cp /tmp/foo_dir <some-pod>:/tmp/bar_dir

  # Copy /tmp/foo local file to /tmp/bar in a remote pod in a specific container
  kubectl cp /tmp/foo <some-pod>:/tmp/bar -c <specific-container>

  # Copy /tmp/foo local file to /tmp/bar in a remote pod in namespace <some-namespace>
  kubectl cp /tmp/foo <some-namespace>/<some-pod>:/tmp/bar

  # Copy /tmp/foo from a remote pod to /tmp/bar locally
  kubectl cp <some-namespace>/<some-pod>:/tmp/foo /tmp/bar

Options:
  -c, --container='': Container name. If omitted, the first container in the pod will be chosen

Usage:
  kubectl cp <file-spec-src> <file-spec-dest> [options]

Use "kubectl options" for a list of global command-line options (applies to all commands).

Basically the default behavior of kubectl cp command is a merge of the content of source and destination directory. Let's say we have local directory /tmp/test containing:

/tmp/test$ ls
different_file.txt

with single line of text "some content". If we copy our local /tmp/test directory to /tmp directory on our Pod, which already contains test folder with a different file, let's say testfile.txt, the content of both directories will be merged, so our destination /tmp/test will contain eventually:

/tmp/test# ls
different_file.txt  testfile.txt

If we change the content of our local different_file.txt to "yet another content" and run again the command:

kubectl cp /tmp/test pod-name:/tmp

it will only override the destination different_file.txt which is already present in the destination /tmp/test directory.

Currently there is no way to override this default behavior.

-- mario
Source: StackOverflow
2/14/2020

Instead of doing "kubectl cp" everytime for your directory, mount your local directory to your pod using "volume mounts".

-- anmol agrawal
Source: StackOverflow